Energy in NatureEssential Knowledge for Naturalists
Without energy, there would be stillness, and more stillness. We would not exist, because there would be no motivating force to reality. If matter existed without energy (and that is perhaps a big if, since matter can become energy and energy can become matter), it would be in either one infinitesimally small spot, with infinite density, or it would be dispersed over an infinite space with little density. Which ever of these extremes is more accurate, it is safe to say that I would not be here writing this web site, and you would not be reading what I have written.
Energy is an integral part of Nature. But, just what is energy? Energy is defined as the ability to do work, or a motivating force. There are generally two types of energy: Potential Energy. and Kinetic Energy. Potential energy is stored energy, while kinetic energy is active, moving energy. For example, a lake full of still water holds potential energy. The water flowing over the falls contains kinetic energy.
What other forms of potential energy can you think of? What about fat in animal cells, or the starch in tubers? This chemical energy is stored for future use, and represents potential energy.
A moving or acting object has kinetic energy. An example- a falling leaf has kinetic energy, while a leaf on the tree has potential energy. What other examples from Nature might you imagine? Raindrops? Winds? Ocean currents?
There are some basic laws that deal with energy in Nature. The first principle in dealing with energy is that energy can be neither created nor destroyed. This is known as the first law of thermodynamics. This may seem a bit strange, because we humans seem to be creating energy all the time. We build nuclear power plants. We create electricity from the wind. We burn coal. We push the gas pedal on our cars. These things all create energy, right?
Energy cannot be created. It can take on new forms by being transformed. For example, coal contains a vast amount of energy. We burn it to create heat, which boils water to create steam. The steam turns turbines, which in turn produce your electricity. The energy used to make the electrical energy that flows in our wires was not created by a turbine. It was simple transformed from stored solar energy into electricity. Coal is the pressurized and heated remains of ancient plants which absorbed sunlight, grew, and then were preserved until current times. When we burn the coal, we are simply releasing stored energy.
The second important law to remember in dealing with energy in Nature is known as the Second Law of Thermodynamics. It states that disorder (entropy) tends to increase over time in a closed system. In plain English, this means that if you do not put some energy into keeping things organized, everything will eventually be a mess. Example: If a plant does not get nutrients from the soil and the sunlight, its cells begin to break down, and the plant dies. What other examples can you see out in Nature?
Now, if a closed system runs down eventually, why is that? You would think that since energy can be neither created nor destroyed under the first law, that the energy would re-cycle, and everything would keep on goingólike a perpetual motion machine. Problem is, during the energy transformations, some energy is nearly always transformed into heat, which dissipates and is hard to recover.
All energy on earth comes from the sun. Solar rays pound down on us, causing plants to create sugars. Consumers, like cows or deer, or people, eat the plants, transforming some of the plant energy into growth and motion, and the remainder of the plant energy is lost to heat. Then, consumers and producers die. The left over energy of the plants and animals then is released by the decomposers. The decomposers facilitate the re-assimilation of the component parts of the plants and animals back into the cycle, both as energy and as nutrients for future plants and animals. Without the energy from the sun, however, the system would break down rather quickly.
Energy is a big issue in Nature, and much of animal behavior, and plant chemistry can be attributed to the quest for fuel. The HyperPhysics pages of the University of Georgia provide a nice overview of energy dynamics in plants and animals.